Unbalance to balance converter?

[laidick]

I want to have very long cable (15meter) for subwoofer but pre only has RCA output, and subwoofer has XLR input.
I believe it's best to use XLR for long run, so I am looking for a unbalance to balance device, if possible have voltage gain would be best.
Is there such device available?

Thanks.

 

[Kal Rubinson]

Such devices are common in the pro/studio market.

 

[mansr]

Something like this, perhaps: https://www.neutrik.co.uk/product/na2m-d2b-tx

 

[dasdoing]

traditionaly a DI box is used

 

[laidick]

Something like this, perhaps: https://www.neutrik.co.uk/product/na2m-d2b-tx

Thanks
Does this one any difference than connect pin 1/3 as usual XLR to RCA ?

 

[laidick]

Such devices are common in the pro/studio market.

Could you have some links for my reference please ?
Thanks

 

[Laserjock]

Could you have some links for my reference please ?
Thanks

ART has a few I believe

 

[Wayne A. Pflughaupt]

I want to have very long cable (15meter) for subwoofer but pre only has RCA output.

I wouldn't have a problem running an unbalanced cable that length for a subwoofer, providing it has an adequate shield.

Regards,
Wayne A. Pflughaupt

 

[AnalogSteph]

The length itself is less of a problem than potential ground loops in the setup. A sub with XLR inputs is not unlikely to be IEC Class I - good luck trying to use a PC as the source with an unbalanced connection then.

 

[laidick]

Thanks all for the tips

 

[Kal Rubinson]

Thanks
Does this one any difference than connect pin 1/3 as usual XLR to RCA ?

Yes, indeed.
Miniature transformer balancing adapters
Low cost solution for unbalanced/balanced line conversion and passive DI applications, where no earth or gain switching is required
Audio transformer 1:1
Impedance ratio: 200:200
Source/load impedance in Ohm: 200/2k, (600/10k)
Max. Input level (@ 50 Hz, 1% THD): -3 dBu

 

[dasdoing]

Low cost solution

though for 2/3 of the price of it you can find full dual channel DIs eg: https://www.amazon.com/Premium-Dire...dp/B00356J8KE/ref=psdc_11975581_t1_B014QB4JIM

not sure if he actualy need the atenuation features? can a pre be regulated to -3 dBu? the "problem" is that balanced dubbles the input signal

 

[Kal Rubinson]

Low cost solution

Actually, that was all quoted from the advertisement that was linked to by another poster.
Yes, there may be "lower cost" solutions.

 

[sergeauckland]

The problem with all 'low cost' solutions that use a transformer, is that decent transformers cost a lot of money and so can't be low cost.
The main limitations are at low frequencies where inexpensive transformers are limited in level at low frequencies, so not suitable for driving a subwoofer.

For a modest distance like 15m, (and as was mentioned above, 15m isn't long) I would first try a well screened unbalanced cable like RG6 as it's cheap enough that if it doesn't work, it can be used for other things. I would try first connecting the inner to XLR pin 2, screen to pins 1 and 3 strapped together. If one gets audible hum, then remove the link to pin 1, leaving pin three to the screen. Only if that doesn't work either would it be advisable to use a balanced cable and some sort of unbalance-balanced converter. To keep costs down, that would need to be an active device, not a passive transformer, I use the Behringer DI120 and an external 9v power supply, and whilst not the best, it's quite good enough at line level.

S.

 

[BostonJack]

The problem with all 'low cost' solutions that use a transformer, is that decent transformers cost a lot of money and so can't be low cost.
The main limitations are at low frequencies where inexpensive transformers are limited in level at low frequencies, so not suitable for driving a subwoofer.

For a modest distance like 15m, (and as was mentioned above, 15m isn't long) I would first try a well screened unbalanced cable like RG6 as it's cheap enough that if it doesn't work, it can be used for other things. I would try first connecting the inner to XLR pin 2, screen to pins 1 and 3 strapped together. If one gets audible hum, then remove the link to pin 1, leaving pin three to the screen. Only if that doesn't work either would it be advisable to use a balanced cable and some sort of unbalance-balanced converter. To keep costs down, that would need to be an active device, not a passive transformer, I use the Behringer DI120 and an external 9v power supply, and whilst not the best, it's quite good enough at line level.

S.

I vote for the Behringer DI120, its low cost, reasonable specs, has a ground lift switch. I used one to run iPad, laptop audio out stereo to dual XLR cables to a sound board at the back of the hall. Very high induced interference immunity. We were running a four speaker PA system so super high fidelity wasn't an issue, but signal quality seemed acceptable. Yup, takes a 9V battery. Best of luck.

 

[Rja4000]

If you really want to go for a true balanced XLR, I'm pretty sure nothing can beat the proposed Neutrik adapter.
It has a 1:1 transformer, and the Neutrik name on it.
Most passive DIs, like the excellent Radial Engineering JDI, lower the signal to microphone level (-38dB for the JDI), which is probably not what you want.

But, again, 15m at line level, for a sub signal, is not "long".
"Long" is 30m and more, for microphone level (mV).

(If you don't like the red RCA, you may also have it in black
https://www.neutrik.co.uk/product/na2m-d0b-tx
Be careful about level:
Max. input level @ 50 Hz at 1% THD: -3 dBu
If you feed it with max -10dBV, that should be good)

 

[sergeauckland]

If you really want to go for a true balanced XLR, I'm pretty sure nothing can beat the proposed Neutrik adapter.
It has a 1:1 transformer, and the Neutrik name on it.
Most passive DIs, like the excellent Radial Engineering JDI, lower the signal to mictophone level, which is probably not what you want.

But, again, 15m at line level, for a sub signal, is not "long".
"Long" is 30m and more, for microphone level (mV).

As much as I admire Neutrik, that particular adapter I think is rather poor. It only handles a level of -3dBu at 50Hz and with 1% distortion, so at sub-woofer levels, down to 20Hz, the distortion will be a lot higher and/or the maximum level a lot lower.

-3dBu is only just over 500mV so unless the subwoofer is unusually sensitive, the maximum output is insufficient.

That Neutrik device I think is far more useful for stage use where its solidity will be appreciated and the LF limitations possibly less problematic.

S.

 

[Rja4000]

As much as I admire Neutrik, that particular adapter I think is rather poor. It only handles a level of -3dBu at 50Hz and with 1% distortion, so at sub-woofer levels, down to 20Hz, the distortion will be a lot higher and/or the maximum level a lot lower.

-3dBu is only just over 500mV so unless the subwoofer is unusually sensitive, the maximum output is insufficient.

That Neutrik device I think is far more useful for stage use where its solidity will be appreciated and the LF limitations possibly less problematic.

S.

I just noted and added to my post above before reading yours.

Then, go for the real thing
https://www.jensen-transformers.com/product/media-1/

Or, cheaper, https://www.radialeng.com/product/prodi/specifications

But, to be fair, I'm not sure the level loss would not be a problem.

 

[Rja4000]

If I had to run 40m cable, I'd probably end up using this instead, Tape in to main output.
https://mackie.com/sites/default/files/PRODUCT RESOURCES/SPECS/Spec_Sheets/802VLZ4_SS.pdf

 

[Veri]

I want to have very long cable (15meter) for subwoofer but pre only has RCA output, and subwoofer has XLR input.
I believe it's best to use XLR for long run, so I am looking for a unbalance to balance device, if possible have voltage gain would be best.
Is there such device available?

Thanks.

If you want a 2V to proper 4V XLR output converter I recommend one based on the texas instruments DRV134 chip:
https://www.audiosciencereview.com/...ina）drv134-rca-to-xlr-adaptor-converter.9948/